Wafer position calibration device for vertical furnace and calibration method thereof

Abstract

The application provides a wafer position calibration device of a vertical furnace and a calibration method thereof, which comprises: a wafer boat for carrying wafers; a detection device comprising a first circular slide rail, a plurality of first guide rods, a plurality of first sliding blocks and a plurality of wafer detection units; each first guide rod is slidably assembled on the first circular slide rail in a circumferential direction; each first sliding block is slidably assembled on the corresponding first guide rod in an axial direction; an adjusting device comprising a second circular slide rail, a second guide rod, a second sliding block and a mechanical hand; a control system configured to receive position information collected by each layer wafer detection unit, calculate the offset of each layer wafer relative to the center of the wafer boat, and drive the mechanical hand to rise to the corresponding height of the wafer to be adjusted and adjust the position according to the offset. By introducing the cooperative control mechanism of "multi-point synchronous detection-wafer offset real-time calculation-deviation wafer targeted calibration", the position of the wafer in the wafer boat can be calibrated in situ.

Description

Technical Field

[0001] This application relates to the field of vertical furnace technology, specifically to a wafer position calibration device and calibration method for a vertical furnace. Background Technology

[0002] Vertical furnaces, as core equipment in semiconductor device manufacturing, are widely used in critical processes such as wafer oxidation, diffusion, and thin film deposition (e.g., chemical vapor deposition). When performing these processes in a vertical furnace, the wafer needs to be precisely mounted on the slots of a wafer boat. The concentricity of the wafer and the boat directly affects the uniformity and consistency of the film thickness after the process. If the wafer and the boat are not concentric, a significant deviation will occur, leading to uneven heating or gas diffusion on the wafer surface. This will cause the film thickness deviation to exceed process requirements, ultimately affecting the performance and yield of the semiconductor device.

[0003] However, existing vertical furnaces generally lack the function of calibrating the position of wafers on the wafer boat. They can only indirectly infer the wafer position deviation by relying on the film thickness deviation after the process. They cannot detect and calibrate the position of wafers one by one in real time before the process, making it difficult to effectively guarantee the process stability and product yield of vertical furnaces.

[0004] Therefore, existing technologies have shortcomings and need to be improved and developed. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer position calibration device and calibration method for a vertical furnace, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A wafer positioning calibration device for a vertical furnace, comprising:

[0008] Crystal boats are used to carry multiple layers of wafers along the height direction;

[0009] The detection device includes a first circular slide rail, a plurality of first guide rods, a plurality of first sliders, and a plurality of wafer detection units, wherein the number of first guide rods, first sliders, and wafer detection units are the same and correspond one-to-one;

[0010] The first circular slide rail is coaxially sleeved on the outside of the crystal boat; each first guide rod is slidably mounted on the first circular slide rail along the circumference.

[0011] Each first slider is slidably mounted on its corresponding first guide rod along the axial direction;

[0012] Each of the first sliders is fixed with a wafer detection unit, which is used to collect the position information of the corresponding wafer edge;

[0013] The adjustment device includes a second circular slide rail, a second guide rod, a second slider, and a robotic arm;

[0014] The second circular slide rail is coaxially sleeved on the outside of the crystal boat;

[0015] The second guide rod is slidably mounted on the second circular slide rail in the circumferential direction;

[0016] The second slider is slidably mounted on the second guide rod along the axial direction;

[0017] The robotic arm is fixed to the second slider and is used to grasp and adjust the position of the wafer in the wafer boat;

[0018] The control system, which is connected to the wafer inspection unit and the robot arm respectively, is configured to: receive the position information collected by the wafer inspection unit of each layer, calculate the offset of each wafer layer relative to the center of the wafer boat, and drive the robot arm to rise and fall to the height corresponding to the wafer to be adjusted and adjust its position according to the offset.

[0019] The wafer inspection unit includes a CCD camera and a laser rangefinder. The CCD camera is used to acquire image information of the wafer edge, and the laser rangefinder is used to measure the distance from the wafer surface to a preset reference surface.

[0020] The wafer position calibration device for the vertical furnace also includes:

[0021] A ring-shaped fill light is provided, with each ring-shaped fill light corresponding to a wafer inspection unit, to provide illumination when the wafer inspection unit acquires wafer position information.

[0022] The number of detection units is N (N≥3). When inspecting the wafer, the N wafer detection units are evenly distributed along the circumference of the first circular slide rail, and the center angle between two adjacent wafer detection units is 360° / N.

[0023] The robotic arm has a flexible gripper at its end, which is used to hold the wafer. A pressure sensor is located on the inside of the flexible gripper, which is used to detect the contact force between the flexible gripper and the wafer surface in real time.

[0024] The wafer position calibration device for the vertical furnace also includes:

[0025] The outer tube is closed at the top and open at the bottom.

[0026] The inner tube is open at both ends and is coaxially installed inside the outer tube.

[0027] The base is used to support the crystal boat and to fitably seal the open ends of the outer and inner tubes;

[0028] The drive assembly, located below the base, is used to drive the base and the crystal boat on it to move up and down along the axial direction of the outer tube, and to drive the base and the crystal boat on it to rotate around the central axis of the outer tube.

[0029] The wafer position calibration device for the vertical furnace also includes:

[0030] The outer tube is closed at the top and open at the bottom.

[0031] The inner tube is closed at the top and open at the bottom, and is coaxially installed inside the outer tube.

[0032] The base is used to support the crystal boat and to fitably seal the open ends of the outer and inner tubes;

[0033] The drive assembly, located below the base, is used to drive the base and the crystal boat on it to move up and down along the axial direction of the outer tube, and to drive the base and the crystal boat on it to rotate around the central axis of the outer tube.

[0034] A wafer position calibration method for a vertical furnace, applied to a wafer position calibration apparatus for a vertical furnace as described in any of the above claims, comprising:

[0035] Preparation before calibration: Fix the crystal boat in the calibration station, and drive each first guide rod to move circumferentially along the first circular track through the control device, while driving each first slider to move up and down along the corresponding first guide rod, so that multiple wafer detection units reach the preset detection angle position and the same detection height position respectively;

[0036] Wafer inspection: The control device drives multiple first sliders to move synchronously along their corresponding first guide rods, thereby driving multiple wafer inspection units to scan each layer of wafers layer by layer along the same height and collect the position information of each layer of wafers; based on the position information of the same layer of wafers collected by each inspection unit, the offset of each layer of wafers relative to the center of the wafer boat is calculated.

[0037] Wafer adjustment: The offset of each wafer layer is compared with a preset threshold. When the offset of the wafer exceeds the preset threshold, the control device drives the robot arm to rise and fall to the height corresponding to the wafer to be adjusted and adjust its position.

[0038] This includes, after wafer adjustment:

[0039] Repeat the wafer inspection steps and calculate whether the offset of each wafer layer exceeds the preset threshold.

[0040] If not, wafer adjustment will not be repeated;

[0041] If so, repeat the wafer adjustment.

[0042] This includes, after not performing wafer adjustments:

[0043] Reset after calibration: The control device drives multiple first guide rods to move circumferentially along the first circular track, and simultaneously drives each first slider to move up and down along the corresponding first guide rod, so that multiple wafer detection units are reset to the detection angle position and detection height position before calibration.

[0044] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0045] By introducing a collaborative control mechanism of "multi-point synchronous detection - real-time wafer offset calculation - targeted calibration of deviated wafers," the position of the wafer in the wafer boat can be calibrated in situ with high precision and efficiency. This reduces the offset of each wafer layer relative to the center of the vertical furnace, avoiding problems such as uneven airflow distribution, temperature field distortion, and thin film deposition thickness differences caused by wafer eccentricity. This improves the yield and consistency of semiconductor wafers in key thermal processing processes such as oxidation, diffusion, and annealing. Simultaneously, this collaborative control mechanism only makes targeted adjustments to wafers with offsets exceeding a preset threshold, avoiding invalid operations and reducing wafer calibration time. It is suitable for scenarios requiring high wafer positional accuracy and process stability. Attached Figure Description

[0046] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0047] Figure 1 A schematic diagram of the structure of a wafer position calibration device for a vertical furnace provided in an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the structure of a wafer position calibration device for a vertical furnace after calibration, provided in an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the structure of a wafer position calibration device for another vertical furnace provided in an embodiment of the present invention;

[0050] Figure 4 This is a schematic flowchart of a wafer position calibration method for a vertical furnace provided in an embodiment of the present invention.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1. Crystal boat; 11. Upper disk; 12. Lower disk; 13. Support column; 131. Slot; 2. Wafer; 3. Detection device; 31. First circular slide rail; 32. First guide rod; 33. First slider; 34. Wafer detection unit; 4. Adjustment device; 41. Second circular slide rail; 42. Second guide rod; 43. Second slider; 44. Robotic arm; 5. Outer tube; 6. Inner tube; 7. Base; 8. Drive assembly. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0054] Furthermore, the directional terms used in this invention, such as [up], [down], [front], [back], [left], [right], [inside], [outside], and [side], are merely for reference to the accompanying drawings. Therefore, the directional terms used are for illustrating and understanding this invention, and not for limiting it. In the various figures, structurally similar units are represented by the same reference numerals. For clarity, the various parts in the figures are not drawn to scale. Additionally, some well-known parts may not be shown in the figures.

[0055] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0057] like Figure 1 The diagram shown is a schematic representation of a wafer 2 position calibration device using a vertical furnace provided in an embodiment of the present invention. This vertical furnace is mainly used for key processes such as oxidation, diffusion, and thin film deposition (e.g., CVD) of semiconductor wafers 2, achieving improved mass production efficiency through simultaneous processing of multilayer wafers 2. It should be noted that, under normal circumstances, the wafer boat 1 is configured to be fully loaded with multilayer wafers 2 in its actual working state. However... Figure 1 In the image below, only a portion of wafer 2 is shown to more clearly demonstrate the structure behind wafer 2.

[0058] The wafer 2 position calibration device of the vertical furnace includes:

[0059] Crystal boat 1, used to carry multilayer wafers 2 along the height direction;

[0060] The detection device 3 includes a first circular slide rail 31, a plurality of first guide rods 32, a plurality of first sliders 33, and a plurality of wafer detection units 34. The number of first guide rods 32, first sliders 33, and wafer detection units 34 are the same and correspond one-to-one.

[0061] The first circular slide rail 31 is coaxially sleeved on the outside of the crystal boat 1; each first guide rod 32 is slidably mounted on the first circular slide rail 31 in the circumferential direction;

[0062] Each first slider 33 is slidably mounted on the corresponding first guide rod 32 along the axial direction;

[0063] Each of the first sliders 33 is fixed with a wafer detection unit 34, which is used to collect the position information of the corresponding wafer 2 edge;

[0064] The adjustment device 4 includes a second circular slide rail 41, a second guide rod 42, a second slider 43, and a robotic arm 44;

[0065] The second circular slide rail 41 is coaxially sleeved on the outside of the crystal boat 1;

[0066] The second guide rod 42 is slidably mounted on the second circular slide rail 41 in the circumferential direction;

[0067] The second slider 43 is slidably mounted on the second guide rod 42 along the axial direction;

[0068] The robotic arm 44 is fixed to the second slider 43 and is used to grasp and adjust the position of the wafer 2 in the crystal boat 1;

[0069] The control system (not shown in the figure) is connected to the wafer inspection unit 34 and the robot arm 44 respectively, and is configured to: receive the position information collected by the wafer inspection unit 34 of each layer, calculate the offset of each wafer 2 relative to the center of the crystal boat 1, and drive the robot arm 44 to rise and fall to the height corresponding to the wafer 2 to be adjusted and adjust its position according to the offset.

[0070] In this embodiment of the invention, the crystal boat 1 includes an upper disk 11, a lower disk 12, and multiple support pillars 13. Generally, the crystal boat 1 is configured to be fully loaded with multiple layers of wafers 2 in its actual working state. Figure 1To more clearly demonstrate the structure behind wafer 2, only a portion of wafer 2 is shown. The crystal boat 1 can be made of high-purity quartz to prevent metal ion contamination of the wafer 2 surface. The support pillars 13 of the crystal boat 1 have multiple slots 131 along their height. The spacing of each set of slots 131 is adapted to the thickness of wafer 2 (e.g., when adapting to 300mm or 450mm wafer 2, the slot spacing can be set to 10-15mm), allowing for stable support of 25-100 layers of wafer 2, with a certain gap (approximately 2-3mm) between each layer to ensure smooth airflow across the upper and lower surfaces of each wafer 2.

[0071] In this embodiment of the invention, a first circular slide rail 31 is coaxially sleeved on the outside of the crystal boat 1, with its center coinciding with the central axis of the crystal boat 1 to ensure the consistency between the detection reference and the bearing reference of the wafer 2. Each first guide rod 32 is slidably mounted on the first circular slide rail 31 in the circumferential direction, and the circumferential distribution spacing can be adjusted according to the size of the wafer 2 and the detection accuracy requirements. Each first slider 33 is slidably mounted on the corresponding first guide rod 32 in the axial direction, and has stable axial sliding guidance performance. A wafer detection unit 34 is fixed on each first slider 33. The wafer detection unit 34 is used to collect the position information of the corresponding edge of the wafer 2, so that the offset (Δx, Δy, Δz) of the center (x0, y0, z0) of each layer of wafer 2 relative to the center (x1, y1, z1) of the crystal boat 1 at the corresponding height, as well as the angle offset θ (the angle deviation value between the existing wafer 2 notch position and the ideal wafer 2 notch position) can be calculated based on the collected position information of the wafer 2 edge.

[0072] The number of wafer detection units 34 is N (N≥3). When detecting wafer 2, the N wafer detection units 34 are evenly distributed around the first circular slide rail 31, and the center angle between two adjacent wafer detection units 34 is 360° / N.

[0073] In this embodiment of the invention, the number of wafer detection units 34 is N (N≥3). Through multi-point synchronous detection, the center of the wafer 2 can be calculated and fitted. It should be noted that there is no particular limitation on the number of N; N can be any integer greater than or equal to 3. For example, the number of wafer detection units 34 is 3, and the included angle between the centers of two adjacent wafers 2 is 120°. This uniformly distributed layout of wafer detection units 34 can synchronously collect wafer 2 contour information from different positions on the edge of wafer 2, ensuring the accuracy of the calculated center (x0, y0, z0) of wafer 2.

[0074] The wafer inspection unit 34 includes a CCD camera and a laser range sensor. The CCD camera is used to acquire image information of the edge of the wafer 2, and the laser range sensor is used to measure the distance from the surface of the wafer 2 to a preset reference surface.

[0075] In this embodiment of the invention, the CCD camera has high-precision image acquisition capability, which can clearly capture the contour image information of the edge of wafer 2, so as to facilitate subsequent fitting calculation of the center (x0, y0) and angular offset θ of wafer 2 (the angular deviation value between the existing wafer 2 notch position and the ideal wafer 2 notch position); the laser range sensor adopts high-precision ranging technology, which can accurately measure the vertical distance from the surface of wafer 2 to the preset reference plane (the corresponding wafer 2 surface at the ideal position of the center of each layer of wafer 2 in the crystal boat 1, and the preset reference plane is different for different layers). The two work together to achieve comprehensive acquisition of the position information of the center (x0, y0, z0) of wafer 2.

[0076] The wafer 2 position calibration device of the vertical furnace also includes:

[0077] A ring-shaped fill light (not shown in the figure) is provided in a one-to-one correspondence with the wafer inspection unit 34 to provide illumination when the wafer inspection unit 34 collects the position information of the wafer 2.

[0078] In this embodiment of the invention, the wafer 2 position calibration device of the vertical furnace also includes a ring-shaped supplementary light. This ring-shaped supplementary light is configured in a one-to-one correspondence with the wafer detection unit 34, providing a stable and uniform lighting environment during the wafer detection unit 34's acquisition of wafer 2 position information. Considering that the surface of wafer 2 is mostly smooth and prone to reflective interference, the ring-shaped supplementary light can be flexibly adjusted to a suitable brightness according to the actual detection scenario after being turned on. This ensures that the edge contour of wafer 2 is clearly discernible, providing sufficient light support for the CCD camera to accurately acquire image information, while effectively suppressing reflective phenomena.

[0079] In this embodiment of the invention, the second circular slide rail 41 is coaxially sleeved on the outside of the crystal boat 1. The second circular slide rail 41 can be located outside or inside the first circular slide rail 31. Its circumferential position is adapted to the working radius of the robot arm 44 to ensure the coverage of the wafer 2 adjustment action. The second guide rod 42 is slidably mounted on the second circular slide rail 41 in the circumferential direction, which can drive the robot arm 44 to move in the circumferential direction of the crystal boat 1 to the side position of the target wafer 2. The second slider 43 is slidably mounted on the second guide rod 42 in the axial direction, which can drive the robot arm 44 to perform lifting and lowering movements to match the position of the wafer 2 at different height layers in the crystal boat 1. The robot arm 44 is fixed on the second slider 43 and is used to grasp and adjust the position of the wafer 2 in the crystal boat 1 to realize the adjustment of the wafer 2 eccentricity.

[0080] The robotic arm 44 has a flexible gripper at its end, which is used to hold the wafer 2. A pressure sensor is provided on the inside of the flexible gripper, which is used to detect the contact force between the flexible gripper and the surface of the wafer 2 in real time.

[0081] In this embodiment of the invention, the flexible gripper is made of a highly elastic and wear-resistant material, and can automatically adjust its opening and closing degree according to the size of wafer 2 (4-12 inch wafer 2). The flexible gripper lightly touches the edge of wafer 2 with a constant pressure of 0.1-0.3N, and performs adjustment actions on wafer 2 to be adjusted according to the offset. The offset in the X / Y direction is corrected by the translation of the gripper, and the circumferential deflection is achieved by micro-rotation in the second circular slide rail 41 combined with the torsion of the gripper. During the adjustment process, the pressure sensor provides real-time feedback on the contact force to ensure that wafer 2 is free from scratches and edge chipping. In addition, a miniature CCD camera is built into the front end of the flexible gripper, which can capture the position coordinates of the edge of wafer 2 in real time, and dynamically correct the movement trajectory in combination with the offset of the control device to avoid scratching or collision with adjacent wafer 2.

[0082] In this embodiment of the invention, the control system is signal-connected to the wafer detection unit 34 and the robot arm 44 respectively, and is configured to: receive the position information collected by the wafer detection units 34 of each layer, fit and calculate the offset of each wafer 2 relative to the center of the crystal boat 1 in the X and Y directions, and obtain the offset in the Z direction by combining the height detection data; and generate corresponding adjustment commands according to the calculated offsets, drive the robot arm 44 to rise and fall to the height corresponding to the wafer 2 to be adjusted, and move along the circumference to the target position, and perform translation or rotation adjustment on the wafer 2 until the wafer 2 and the crystal boat 1 are restored to a concentric state.

[0083] like Figure 2 The diagram shows a schematic of the wafer 2 position calibration device for a vertical furnace provided in an embodiment of the present invention. After wafer 2 calibration is completed, a control device drives multiple first guide rods 32 to move circumferentially along a first circular track, while simultaneously driving each first slider 33 to move up and down along the corresponding first guide rod 32, so that multiple wafer detection units 34 are respectively reset to the detection angle position and detection height position before calibration. Subsequently, the outer tube 5 and inner tube 6 are slowly lowered, fitted onto the outside of the crystal boat 1 and sealed, and the vertical furnace enters the subsequent process stage. The wafer 2 position calibration device for the vertical furnace also includes:

[0084] Outer tube 5, the upper end of the outer tube 5 is closed, and the lower end is open;

[0085] Inner tube 6, with its upper and lower ends open, is coaxially located inside outer tube 5;

[0086] The base 7 is used to support the crystal boat 1 and adaptably closes the open ends of the outer tube 5 and the inner tube 6;

[0087] The drive assembly 8, located below the base 7, is used to drive the base 7 and the crystal boat 1 on it to move up and down along the axial direction of the outer tube 5, and to drive the base 7 and the crystal boat 1 on it to rotate around the central axis of the outer tube 5.

[0088] In this embodiment of the invention, the outer tube 5 of the vertical furnace has an overall vertical cylindrical structure and can be made of quartz material to meet the stringent requirements of cleanliness and corrosion resistance in semiconductor processes. The upper end of the outer tube 5 is a closed structure, which can be a horizontal surface seal, an arc-shaped surface seal, or other sealing methods, without limitation. Preferably, the upper end of the outer tube 5 adopts an arc-shaped surface seal design, which can reduce dead angles in the airflow inside the tube and prevent gas from accumulating at the top and forming a local concentration difference. The lower end of the outer tube 5 is an open structure, and preferably, its open edge is provided with a sealing groove, which can cooperate with the base 7 below to achieve a seal. The main function of the outer tube 5 is to construct an independent process chamber space, isolate external air and contaminants, and at the same time, cooperate with the heating system of the equipment (usually arranged around the side wall of the outer tube 5, or around the side wall between the inner tube 6 and the outer tube 5) to provide a high-temperature environment (e.g., 300-1200℃) inside the tube.

[0089] In this embodiment of the invention, the inner tube 6 of the vertical furnace is also a vertical cylindrical structure, and its material is the same as that of the outer tube 5 (or quartz with higher purity is used). Both its upper and lower ends are open. The upper end is open to facilitate the flow and mixing of airflow and reaction gas inside the tube, while the lower end is open to match the support structure of the base 7, which facilitates the entry and exit of the crystal boat 1.

[0090] In this embodiment of the invention, the edge of the base 7 is provided with a sealing element (such as a high-temperature resistant fluororubber sealing ring) that is adapted to the sealing groove at the lower end of the outer tube 5, which can realize the airtight sealing of the internal process cavity of the outer tube 5 and prevent the leakage of reaction gas or the infiltration of external air.

[0091] In this embodiment of the invention, the drive assembly 8 includes a lifting mechanism and a rotating mechanism. The lifting mechanism uses a servo motor in conjunction with a ball screw or a high-precision cylinder to drive the base 7 and the crystal boat 1 to move smoothly up and down axially. The rotating mechanism uses a low-speed servo motor in conjunction with a harmonic reducer to drive the crystal boat 1 to rotate at a low speed of 5-20 r / min, ensuring that the wafer 2 is in uniform contact with the airflow and temperature field.

[0092] like Figure 2 The diagram shown is a structural schematic of a wafer 2 position calibration device for a vertical furnace provided in an embodiment of the present invention. The wafer 2 position calibration device for the vertical furnace further includes:

[0093] Outer tube 5, the upper end of the outer tube 5 is closed, and the lower end is open;

[0094] Inner tube 6, the upper end of which is closed and the lower end is open, is coaxially arranged inside the outer tube 5;

[0095] The base 7 is used to support the crystal boat 1 and adaptably closes the open ends of the outer tube 5 and the inner tube 6;

[0096] The drive assembly 8, located below the base 7, is used to drive the base 7 and the crystal boat 1 on it to move up and down along the axial direction of the outer tube 5, and to drive the base 7 and the crystal boat 1 on it to rotate around the central axis of the outer tube 5.

[0097] In another wafer 2 position calibration device for a vertical furnace provided in this embodiment of the invention, the upper end of the inner tube 6 of the vertical furnace tube is closed, and the lower end is open. The closed end of the inner tube 6 can be a horizontal surface seal, an arc-shaped surface seal, or other sealing methods, and is not limited. Preferably, the upper end of the inner tube 6 adopts an arc-shaped surface seal design, which can reduce the dead angle of airflow inside the tube and avoid gas accumulation at the top to form a local concentration difference.

[0098] This invention provides a wafer 2 position calibration device for a vertical furnace. By introducing a collaborative control mechanism of "multi-point synchronous detection - real-time calculation of wafer 2 offset - targeted calibration of deviation wafer 2," the device can perform high-precision and high-efficiency in-situ calibration of the wafer 2 position in the wafer boat 1. This reduces the offset of each layer of wafer 2 relative to the center of the vertical furnace, avoiding problems such as uneven airflow distribution, temperature field distortion, and thin film deposition thickness differences caused by wafer 2 eccentricity. This improves the yield and consistency of semiconductor wafer 2 in key heat treatment processes such as oxidation, diffusion, and annealing. Simultaneously, this collaborative control mechanism only makes targeted adjustments to wafer 2 with offsets exceeding a preset threshold, avoiding invalid operations and reducing wafer 2 calibration time. It is suitable for scenarios requiring high wafer 2 position accuracy and process stability.

[0099] Based on the wafer 2 position calibration device for a vertical furnace described in the above embodiments, this invention also provides a wafer 2 position calibration method for a vertical furnace, applied to the wafer 2 position calibration device for a vertical furnace as described above. Figure 4 The diagram shown is a schematic flowchart of a wafer 2 position calibration method for a vertical furnace provided in an embodiment of the present invention, including:

[0100] S1, Preparation before calibration: Fix the crystal boat 1 at the calibration station, and drive each first guide rod 32 to move circumferentially along the first circular track through the control device, while driving each first slider 33 to move up and down along the corresponding first guide rod 32, so that multiple wafer detection units 34 reach the preset detection angle position and the same detection height position respectively.

[0101] S2, wafer 2 inspection: The control device drives multiple first sliders 33 to move synchronously along their corresponding first guide rods 32, thereby driving multiple wafer inspection units 34 to scan each layer of wafer 2 at the same height and collect the position information of each layer of wafer 2; based on the position information of the same layer of wafer 2 collected by each inspection unit, the offset of each layer of wafer 2 relative to the center of the crystal boat 1 is calculated.

[0102] S3, wafer 2 adjustment: The offset of each layer of wafer 2 is compared with the preset threshold. When the offset of wafer 2 exceeds the preset threshold, the robot arm 44 is driven by the control device to rise and fall to the height corresponding to the wafer 2 to be adjusted and its position is adjusted.

[0103] In S3, after the adjustment of wafer 2, it also includes:

[0104] Repeat the wafer 2 inspection step and calculate whether the offset of each layer of wafer 2 exceeds the preset threshold.

[0105] If not, then wafer 2 adjustment will not be repeated;

[0106] If so, repeat the wafer 2 adjustment.

[0107] This includes, after not performing wafer 2 adjustments, the following:

[0108] S4, Reset after calibration: The control device drives multiple first guide rods 32 to move circumferentially along the first circular track, and simultaneously drives each first slider 33 to move up and down along the corresponding first guide rod 32, so that multiple wafer detection units 34 are reset to the detection angle position and detection height position before calibration.

[0109] After wafer 2 is assembled into the crystal boat 1, wafer 2 is positionally calibrated. During wafer 2 calibration, the outer tube 5 and inner tube 6 of the vertical furnace are not yet lowered. At this time, the interior of the vertical furnace maintains an open working space, providing unobstructed working space for the testing device 3 and the adjustment device 4, as detailed below:

[0110] S1, Preparation before calibration: Raise and lower the crystal boat 1 to the calibration station and lock it in place using the positioning pins at the bottom of the crystal boat 1, ensuring that the crystal boat 1 itself does not rotate circumferentially or shift axially. The first guide rail on the outside of the vertical furnace moves along the first circular slide rail 31, driving three CCD cameras to move synchronously around the crystal boat 1 to the initial detection position. The camera lenses are used to align with the 3 detection points on the wafer 2 for detection. The ring supplement light is turned on and adjusted to an appropriate brightness (to avoid interference from reflections on the surface of the wafer 2). The laser rangefinder is simultaneously started to preheat, measuring the surface of the wafer 2 against the preset reference surface (the corresponding surface of each layer of wafer 2 at the ideal position of the center of the crystal boat 1, and the preset reference surface for different layers).

[0111] (Different) vertical distances.

[0112] S2, Wafer 2 Inspection: Multiple CCD cameras and laser distance sensors simultaneously scan all wafers 2 in the crystal boat 1 layer by layer at preset intervals (collecting data for each layer of wafer 2) and collect the position information of each layer of wafer 2. Each wafer 2 corresponds to 3 different angles for image acquisition, and the center coordinates (x0, y0) of each wafer 2 are fitted to obtain the center coordinates (x0, y0) of each wafer 2. At the same time, the laser distance sensor is perpendicularly incident on the surface of wafer 2 and collects the height data in the Z direction. The position offset (Δx, Δy, Δz) and angle offset θ of the center of the crystal boat 1 are calculated (the angle deviation between the existing wafer 2 notch position and the ideal wafer 2 notch position).

[0113] S3, Wafer 2 Adjustment: Identify wafers 2 whose center offset and angle offset θ are greater than preset thresholds, mark their layer number and offset information, and drive the robot arm 44 to rise and fall to the height corresponding to the wafer 2 to be adjusted and adjust its position. The preset thresholds for position offset Δx, Δy, and Δz are 0.02 mm, and the preset threshold for angle offset Δθ is 0.1°.

[0114] In addition, the robotic arm 44 is equipped with a flexible gripper at its end, which can automatically adjust its opening and closing degree according to the size of wafer 2 (4-12 inch wafer 2). The flexible gripper gently touches the edge of wafer 2 with a constant pressure of 0.1-0.3N, and performs adjustment actions on wafer 2 to be adjusted according to the offset. The offset in the X / Y direction is corrected by the translation of the gripper, and the circumferential deflection is achieved by micro-rotation in the second circular slide rail 41 combined with the torsion of the gripper. During the adjustment process, the pressure sensor provides real-time feedback on the contact force to ensure that wafer 2 is free from scratches and edge chipping. In addition, a miniature CCD camera is built into the front end of the flexible gripper, which can capture the position coordinates of the edge of wafer 2 in real time. Combined with the offset of the control device, the movement trajectory is dynamically corrected to avoid scratching or collision with adjacent wafers 2.

[0115] S4, Reset after calibration: After completing the adjustment of wafer 2, repeat the wafer 2 detection step. If the offset of all wafers 2 is within the preset threshold, the wafer 2 adjustment step is not repeated, and the reset after calibration step is executed. If there is a wafer 2 offset greater than the preset threshold, adjust the still off-center wafers 2 until the offset of all wafers 2 is within the preset threshold, and then execute the reset after calibration step. Subsequently, lower the outer tube 5 and inner tube 6 of the vertical furnace, fit them onto the outside of the crystal boat 1 and seal them. The vertical furnace then enters the subsequent process stage.

[0116] In this embodiment of the invention, the open space advantage when the outer tube 5 and inner tube 6 are not lowered allows for interference-free operation of wafer 2 inspection and adjustment. Simultaneously, by utilizing a multi-point distributed CCD camera and laser distance sensor in conjunction, wafers 2 whose center position offset and angular offset θ exceed a preset threshold are identified. Their layer number and offset information are marked, and the robotic arm 44 is driven to rise and fall to the corresponding height of the wafer 2 to be adjusted and its position is then adjusted. This method is suitable for scenarios requiring high wafer 2 positional accuracy and process stability.

[0117] This invention provides a wafer position calibration device and method for a vertical furnace. By introducing a collaborative control mechanism of "multi-point synchronous detection - real-time wafer offset calculation - targeted calibration of deviated wafers," it can perform high-precision and high-efficiency in-situ calibration of the wafer position in the wafer boat, reducing the offset of each wafer layer relative to the center of the vertical furnace. This avoids problems such as uneven airflow distribution, temperature field distortion, and thin film deposition thickness differences caused by wafer eccentricity, thus improving the yield and consistency of semiconductor wafers in key heat treatment processes such as oxidation, diffusion, and annealing. Simultaneously, this collaborative control mechanism only performs targeted adjustments on wafers with offsets exceeding a preset threshold, avoiding invalid operations and reducing wafer calibration time. It is suitable for scenarios requiring high wafer position accuracy and process stability.

[0118] The above-described preferred embodiments of the present invention are provided as examples, but it will be apparent to those skilled in the art that such embodiments are provided merely by way of example. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of protection of the invention and therefore cover the modular compositions, equivalents, or alternatives within the scope of these claims.

Claims

1. A wafer position calibration device for a vertical furnace, characterized in that, include: Crystal boats are used to carry multiple layers of wafers along the height direction; The detection device includes a first circular slide rail, a plurality of first guide rods, a plurality of first sliders, and a plurality of wafer detection units, wherein the number of first guide rods, first sliders, and wafer detection units are the same and correspond one-to-one; The first circular slide rail is coaxially sleeved on the outside of the crystal boat; each of the first guide rods is slidably mounted on the first circular slide rail in the circumferential direction; Each of the first sliders is slidably mounted on the corresponding first guide rod along the axial direction; Each of the first sliders is fixed with a wafer detection unit for collecting position information corresponding to the edge of the wafer; The adjustment device includes a second circular slide rail, a second guide rod, a second slider, and a robotic arm; The second circular slide rail is coaxially sleeved on the outside of the crystal boat; The second guide rod is slidably mounted on the second circular slide rail in the circumferential direction; The second slider is slidably mounted on the second guide rod along the axial direction; The robotic arm is fixed to the second slider and is used to grasp and adjust the position of the wafer in the wafer boat; The control system, which is connected to the wafer inspection unit and the robot arm respectively, is configured to: receive the position information collected by the wafer inspection units of each layer, calculate the offset of each wafer relative to the center of the wafer boat, and drive the robot arm to rise and fall to the height corresponding to the wafer to be adjusted and adjust its position according to the offset.

2. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, The wafer inspection unit includes a CCD camera and a laser rangefinder. The CCD camera is used to acquire image information of the wafer edge, and the laser rangefinder is used to measure the distance from the wafer surface to a preset reference surface.

3. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, Also includes: A ring-shaped fill light is provided, which is configured one-to-one with each of the wafer inspection units, and is used to provide illumination when the wafer inspection unit collects the position information of the wafer.

4. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, The number of detection units is N (N≥3). When the wafer is being inspected, the N wafer detection units are evenly distributed along the circumference of the first circular slide rail, and the center angle between two adjacent wafer detection units is 360° / N.

5. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, The end of the robotic arm is equipped with a flexible gripper for holding the wafer. A pressure sensor is provided on the inner side of the flexible gripper for real-time detection of the contact force between the flexible gripper and the wafer surface.

6. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, Also includes: An outer tube, the upper end of which is closed and the lower end is open; The inner tube is open at both ends and coaxially disposed inside the outer tube; A base is used to support the crystal boat and adaptably close the open ends of the outer tube and the inner tube; A drive assembly, located below the base, is used to drive the base and the crystal boat on it to move up and down along the axial direction of the outer tube, and to drive the base and the crystal boat on it to rotate around the central axis of the outer tube.

7. The wafer position calibration device for a vertical furnace as described in claim 1, characterized in that, Also includes: An outer tube, the upper end of which is closed and the lower end is open; The inner tube is closed at the upper end and open at the lower end, and is coaxially disposed inside the outer tube; A base is used to support the crystal boat and adaptably close the open ends of the outer tube and the inner tube; A drive assembly, located below the base, is used to drive the base and the crystal boat on it to move up and down along the axial direction of the outer tube, and to drive the base and the crystal boat on it to rotate around the central axis of the outer tube.

8. A wafer position calibration method for a vertical furnace, applied to the wafer position calibration apparatus of the vertical furnace as described in any one of claims 1 to 7, characterized in that, include: Preparation before calibration: Fix the crystal boat in the calibration station, and drive each of the first guide rods to move circumferentially along the first circular track through the control device, while driving each of the first sliders to move up and down along the corresponding first guide rod, so that the multiple wafer detection units reach the preset detection angle position and the same detection height position respectively. Wafer inspection: The control device drives multiple first sliders to move synchronously along their corresponding first guide rods, thereby driving multiple wafer inspection units to scan each layer of wafers layer by layer along the same height and collect the position information of each layer of wafers; based on the position information of the wafers in the same layer collected by each inspection unit, the offset of each layer of wafers relative to the center of the wafer boat is calculated. Wafer adjustment: The offset of each wafer in each layer is compared with a preset threshold. When the offset of the wafer exceeds the preset threshold, the control device drives the robot arm to rise and fall to the height corresponding to the wafer to be adjusted and adjust its position.

9. The wafer position calibration method for a vertical furnace as described in claim 8, characterized in that, Following the wafer adjustment, the following is also included: Repeat the wafer inspection step and calculate whether the offset of the wafer in each layer exceeds the preset threshold. If not, the wafer adjustment will not be repeated; If so, repeat the wafer adjustment.

10. The wafer position calibration method for a vertical furnace as described in claim 9, characterized in that, After not performing the wafer adjustment, the method also includes: Reset after calibration: The control device drives multiple first guide rods to move circumferentially along the first circular track, and simultaneously drives each first slider to move up and down along the corresponding first guide rod, so that the multiple wafer detection units are reset to the detection angle position and detection height position before calibration.

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